Companies are often dependent on mission-critical network applications to stay productive and competitive. To achieve this, information technology (IT) organizations preferably provide reliable application performance on a 24-hour, 7-day-a-week basis. In this demanding environment, frequent network expansion and day-to-day fire fighting often leave little time for IT managers to manage network performance proactively. Accordingly, IT managers typically rely on some form of system management and/or network management tools to help automate performance management tasks to increase the efficiency of the IT staffs. Even with these tools, IT staffs are typically required to commit resources to integrating and customizing the tools to work in the heterogeneous network environments which may include, for example, hardware from a variety of vendors, executing a variety of operating systems and communication protocols and supporting a variety of application programs for different end user requirements.
Various known system management products track specific information, such as the CPU utilization on a server, server paging and disk access activity, or client application response time. This information may be useful when solving problems on a network. These products can generally be categorized as passive systems or application monitors. This category typically is implemented as software agent technologies that reside on the client or server computers. They generally passively monitor live application transactions and monitor resource utilization. Products in this category include Patrol from BMC Software, Inc., FirstSense Agent from FirstSense Software, Inc., VitalAgent from INS, Luminate Software Corp., and Envive Corp. As they are passive application monitors, they typically support specific application programs. For example, Luminate Software and Envive support the SAP R/3 application. Their measurements are generally neither consistent nor repeatable, as a user's interaction with a given application varies over time. Moreover, they are typically not suited to detecting system slowdowns or failures from the perspective of an end user. Operations for one such passive monitor are described in “Characterizing End-to-End Performance: A VitalSigns Whitepaper,” VitalSigns Software, Inc. 1998.
Another approach to passive monitoring is directed to the network rather than the overall system. On the network side, element managers or passive network monitors are known which may address a specific segment or device on the network. Element managers are generally software designed to manage specific groups of devices, such as routers and switches. Passive network monitors are typically a combination of hardware and software that may, for example, monitor network traffic at the link layer or at the infrastructure devices. Products falling in this category include remote monitor (RMON) probes from NetScout Systems, Inc., Sniffer from Network Associates, NetMetrix from Hewlett-Packard, Application Expert from Optimal Networks Corp., EcoSCOPE from Compuware Corp., and Visual OnRamp from Visual Networks, Inc. These network management tools typically provide information such as packet loss, bit rates, and network utilization. This type of information may be helpful in fixing a network problem after the problem has been identified. However, as with the passive system monitors, these tools generally do not reflect network performance as experienced by a user. These tools are passive, in that they generally watch the network traffic which traverses a network segment or link, rather than actively creating traffic.
Passive network monitors sometimes include a basic scheduler to collect sample data from their data sources. A basic scheduler generally merely specifies the frequency (e.g., once every 15 minutes) at which the management console of the monitor should collect data from the data sources. Passive monitors are limited in that they are typically expensive to scale, only see traffic that is on the network at the time.
Another category of system management tool is active application monitors. These are products that generally measure performance by actively emulating application transactions. These transactions are often referred to as “synthetic” transactions. Products in this category include Ganymede Software Inc.'s Chariot® and Pegasus™ products, as described in U.S. Pat. Nos. 5,838,919, 5,881,237 and 5,937,165, VeriServ from Response Networks, Inc. and SLM from Jyra Research Inc. VeriServ allows an operator to define the types of applications to be monitored, times and days, and the end user locations from which the transactions are to originate. The operator may also choose to define alarm thresholds. Agents installed at the end user location monitor actual sample application transactions to measure performance of the applications operating over the network environment. VeriServ automatically tests applications at a fixed interval. SLM provides the flexibility for the user to schedule synthetic transactions for any interval from 5 minutes to a year. However, as these approaches are also typically directed to a particular application and require that the applications be installed and operating to generate network traffic, they generally only address simple web and database transactions. Also, any new or custom applications may require extensive configuration by the users to allow the tester to interact with the applications. In addition, active network testers add traffic to the communication network being tested, thereby using network resources which would otherwise be available for users.
As the range of information available to IT staffs from network performance tools increases, IT staffs face increasing challenges in attempting to analyze the large volumes of resulting data to identify and respond to problems promptly. The increasing complexity of networks and the variety of applications and users utilizing those networks in a client-server environment makes the challenge even greater for IT staffs. These problems are further exacerbated as networks are typically not static as new hardware and software application programs may be periodically added thereby changing the traffic characteristics on the network and the end user's experience of network performance. It is increasingly important to analyze the actual performance of the network to be tested without the constraints and limitations of these existing tools. It would also be beneficial to provide network performance tools that reduce the level of expertise about network performance and topology required of IT personnel.
One approach to improving the analysis of network performance data is that used with VitalAnalysis™ available from VitalSigns Software, Inc. This system provides a display to a user graphically representing various performance measurements, for example, response time, on a “heat” screen with problem conditions for each of the various performance measurements reflected by an associated color and further providing trend information for the various performance measurements. In addition, the results for each performance measurement may be broken down by application type to assist with identification of particular applications having problems. However, this approach still requires assessment by a user of a number of different performance measurements, each of which may have a variable impact as perceived by different users executing applications on the network being monitored. In addition, complex networks typically include a large number of client and server devices at dispersed geographic locations. Accordingly, it may still be problematic for an IT staff to isolate the cause for a performance problem even after it is detected.